Method for producing anhydrous calcium nitrate powder

Patent metadata

Field	Value
Publication number	US-9908787-B2
Application number	US-201515311528-A
Country	US
Kind code	B2
Filing date	Jun 23, 2015
Priority date	Jun 23, 2014
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

The invention relates to a method for producing an anhydrous powder having a calcium nitrate content of between 92 and 99.9 weight %, a water content of between 0.1 and 8 weight %; and a particle size of between 0.05 and 1.5 mm, wherein the method comprises the step of subjecting a calcium nitrate solution having a water content of between 70 and 15 weight % and a calcium nitrate content of between 30 and 85 weight % to a drying step in an industrial turbo-dryer, resulting in the anhydrous calcium nitrate powder. The invention furthermore relates to such an anhydrous calcium nitrate powder and the use of an industrial turbo-dryer to produce such anhydrous calcium nitrate powder.

First claim

The invention claimed is:

1. A method for producing an anhydrous powder, wherein the method comprises the step of subjecting a calcium nitrate solution having a water content of between 70 and 15 weight % of water and a calcium nitrate content of between 30 and 85 weight % to a drying step, CHARACTERISED IN THAT the calcium nitrate solution is subjected to a drying step performed at a temperature of between 200 and 300° C. in a turbo-dryer,
wherein the turbo-dryer comprises a drum having a horizontal axis and being closed at opposite ends that are provided with openings for the introduction of the solution and a stream of dry air travelling in the same direction, and further comprises a heating jacket for heating the internal wall of the tubular body to a predetermined temperature, and a bladed rotor rotatable supported in the drum, and
wherein the drying step produces the anhydrous calcium nitrate powder having
a calcium nitrate content of between 92 and 99.9 weight %;
a water content of between 0.1 and 8 weight %; and
a particle size of between 0.05 and 1.5 mm;
wherein the anhydrous calcium nitrate produced in the drying step has a calcium nitrate content and a water content adding up to 100 weight %.

2. The method according to claim 1 , characterized in that the drying step is performed at a temperature of between 240 and 280° C.

3. The method according to claim 1 , characterized in that the calcium nitrate solution has a water content of between 45 and 50 weight % and a calcium nitrate content of between 55 and 50 weight %.

4. The method according to claim 1 , wherein the drying step produces anhydrous calcium nitrate powder having a content of calcium nitrate between 95 and 99.9 weight % and a water content of between 0.1 and 5 weight %.

5. The method according to claim 4 , wherein the produced anhydrous calcium nitrate powder has a content of calcium nitrate between 96 and 99.9 weight % and a water content of between 0.1 and 4 weight %.

6. The method according to claim 1 , wherein the drying step produces anhydrous calcium nitrate powder having a particle size between 0.1 and 1 mm.

7. The method according to claim 1 , wherein the drying step produces anhydrous calcium nitrate powder having a particle size of between 0.08 and 1 mm.

8. The method according to claim 1 , wherein the calcium nitrate solution is purified before being subjected to the drying step.

Assignees

• Yara Int Asa

Inventors

• Obrestad Torstein

Classifications

• F26B11/028

  Arrangements for the supply or exhaust of gaseous drying medium for direct heat transfer, e.g. perforated tubes, annular passages, burner arrangements, dust separation, combined direct and indirect heating · CPC title

• F26B3/06

  the gas or vapour flowing through the materials or objects to be dried (F26B3/14 takes precedence) · CPC title

• C01F11/44 Primary

  Concentrating; Crystallisating; Dehydrating; Preventing the absorption of moisture or caking · CPC title

• C01P2006/82

  water content · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title